In the related art, a piezoelectric device is known that includes a substrate, a piezoelectric layer that is provided above the substrate and electrodes that are arranged such that the piezoelectric layer is interposed between the electrodes, as described in Japanese Unexamined Patent Application Publication No. 2009-260723 (Patent Document 1) for example. Such a piezoelectric device is used in filters, actuators, sensors and so forth.
As an example of such a piezoelectric device, a MEMS device that includes a transducer, a substrate and a temperature compensation element is disclosed in paragraphs 0017 to 0023 and FIGS. 1A and 1B of U.S. Patent Application Publication No. 2010/0195851 A1 (Patent Document 2). The transducer is, for example, a piezoelectric ultrasonic transducer that undergoes bending vibration and is arranged above the substrate. The temperature compensation element is a heater element, for example, and is arranged on the substrate around the periphery of the transducer on the lower surface side of the transducer.
Furthermore, a 3×3 sensor array that includes sensor elements, a substrate and heater elements is disclosed in paragraphs 0070 to 0076 and FIGS. 2A and 2B of U.S. Patent Application Publication No. 2010/0134209 A1 (Patent Document 3). Each of the sensor elements is a piezoelectric resonance element that includes a piezoelectric layer and two electrodes that are arranged on an upper surface of the piezoelectric layer and the sensor elements are arranged on the substrate. The heater elements are arranged on the substrate around the peripheries of the sensor elements.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-260723
Patent Document 2: U.S. Patent Application Publication No. 2010/0195851 A1
Patent Document 3: U.S. Patent Application Publication No. 2010/0134209 A1